Messages in this thread | | | From | Jesse Barnes <> | Subject | Re: Lossy interrupts on x86_64 | Date | Wed, 12 Sep 2007 09:29:52 -0700 |
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On Wednesday, September 12, 2007, Randy Dunlap wrote: > On Wed, 12 Sep 2007 08:33:15 -0700 Jesse Barnes wrote: > > I just narrowed down a weird problem where I was losing more than > > 50% of my vblank interrupts to what seems to be the hires timers > > patch. Stock 2.6.23-rc5 works fine, but the latest (171) kernel > > from rawhide drops most of my interrupts unless I also have another > > interrupt source running (e.g. if I hold down a key or move the > > mouse I get the expected number of vblank interrupts, otherwise I > > get between 3 and 30 instead of the expected 60 per second). > > > > Any ideas? It seems like it might be bad APIC programming, but I > > haven't gone through those mods to look for suspects... > > Also tickless? (NO_HZ ?) > > I think I've seen some emails about tickless and keystrokes being > needed to cause interrupts... but I'm not postive about it. > > but you said "any ideas"
Yeah, there's NO_HZ in the rawhide kernel too, but I'm getting timer ticks normally afaict, it's just vblank interrupts that get lost...
/proc/interrupts on this machine (from NO_HZ, hires kernel):
[jbarnes@jbarnes-t61 ~]$ cat /proc/interrupts CPU0 CPU1 0: 290050 289541 IO-APIC-edge timer 1: 3862 3956 IO-APIC-edge i8042 8: 0 0 IO-APIC-edge rtc0 9: 1632 1643 IO-APIC-fasteoi acpi 12: 183662 183926 IO-APIC-edge i8042 14: 20626 20717 IO-APIC-edge libata 15: 0 0 IO-APIC-edge libata 16: 46812 46825 IO-APIC-fasteoi yenta, uhci_hcd:usb3, i915@pci:0000:00:02.0 17: 63715 63653 IO-APIC-fasteoi uhci_hcd:usb4, HDA Intel, firewire_ohci, iwl4965 18: 0 0 IO-APIC-fasteoi uhci_hcd:usb5 19: 52 36 IO-APIC-fasteoi ehci_hcd:usb7 20: 43 46 IO-APIC-fasteoi uhci_hcd:usb1 21: 0 0 IO-APIC-fasteoi uhci_hcd:usb2 22: 2 1 IO-APIC-fasteoi ehci_hcd:usb6 2297: 937 944 PCI-MSI-edge eth0 2298: 12392 12402 PCI-MSI-edge ahci NMI: 0 0 LOC: 290913 335027 ERR: 0
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